KERNEL5.10.0-0.deb10.30-rt-amd64 #1 SMP PREEMPT_RT -ethercat not run

Hi .
On debian buster with kernel 4.19.0-27-rt-amd64 , my ethercat configuration run good.
I have refresh kernel 5.10.0-0-rt-amd64 with reposity.
Pc run good , but ethercat not run .
The ethernet configuration address are the same , not changed.
The drive not are see.

what could be the cause ?

if you share some terminal output maybe all more clear .... any how if you have update maybe need update ethercat masteer or maybe you have changed pc so need to change mac adress ata least. Try to write on terminal: ethercat master or sudo ethercat master .... so you can see if it is problematic.

regards